Grit, passion and perseverance for long-term goals, is strongly related to success in goal attainment even under challenging circumstances. We investigated how grit relates to three aspects of well-being: psychological well-being (PWB), satisfaction with life, and harmony in life. This relationship is approached through organismic valuing theory, which proposes that people are naturally motivated to grow towards their highest potential; grit is proposed as being akin to such growth motivation. In two studies (Study 1 with 196 university students, and Study 2 with 396 non-students), direct and indirect (mediating) effects between grit and well-being were investigated. Sense of coherence (SOC) and authenticity were used as mediators, and gender as a moderator. Grit was positively related to all well-being factors, and SOC and authenticity were significant mediators (complementary for PWB and indirect-only for satisfaction with life and harmony in life). This suggests that grittiness in goal pursuits requires both a sense that the world is coherent and an authentic connection with the self in order for it to fully benefit well-being. No gender moderation was found.